1. Field of the Invention
The present invention relates to a re-transfer printing machine and a re-transfer printing method. Particularly, the present invention relates to a technique which is superior in economical efficiency while enhancing the security of information printed on an objected to be printed.
2. Description of Related Art
Hitherto, a technique of preventing interpolation and counterfeit of an objected to be printed, such as card, thereby to enhance its security has been variously contemplated and made practicable.
It is preferable to apply such a technique on an object to be printed, especially, a variety of cards (in detail, credit card, ID card, certification card, etc).
For cards as personal identifiers, it is often the case that an owner's facial portrait is printed on the card. In the situation, there is an increasing movement of using sublimation ink(s) suitable for high-grade photographic printing in addition to fusible ink suitable for printing characters.
In the technology of enhancing the security of a card, there is known a technique of using invisible ink thereby to make printed information (e.g. photo or data) invisible normally. With specific light within a specific wavelength band (e.g. ultraviolet light), the invisible ink becomes fluorescent to be visible although it becomes invisible under visible light normally. For instance, Japanese Patent Laid-Open Publication No. 5-52069 discloses such a technique of printing a certificate code on a card with the use of invisible ink.
In addition, a technique of manufacturing a card with the use of both sublimation ink and invisible ink is disclosed in Japanese Patent Laid-Open Publication No. 11-321166. In the above publication, there is described an identification (ID) card whose security can be enhanced as a result of preventing the card from being tampered or counterfeiting. This identification card is provided with a facial-portrait area on which a facial portrait (image) is printed by using the sublimation ink. On the facial-portrait area, additionally, owner's inherent information is printed by using fluorescent ink that becomes fluorescent to be visible due to irradiation of ultraviolet light.
Regarding a method of manufacturing this card, Japanese Patent Laid-Open Publication No. 11-321166 further discloses the use of a sublimation transfer ribbon. The sublimation transfer ribbon has respective sublimation-dye layers in yellow (Y), magenta (M), cyan (C) and black (B) arranged on a ribbon base, in this order. The sublimation transfer ribbon further includes fluorescent ink and a protecting layer arranged on the ribbon base so as to follow these sublimation-dye layers.